Before starting treatment, talk with your doctor, nurse, or another member of your health care team about any other medical conditions you may have.

Because drugs you may be taking for other health problems can interact with cancer treatments or supportive care medications, you may need to temporarily stop taking them.

While you are coping with the physical, emotional, and social challenges associated with a diagnosis of cancer, it can be easy to ignore other chronic (long-lasting) medical conditions you may have, such as diabetes or heart disease. However, the way you manage these conditions often influences the success of your cancer treatment plan.

All chronic medical conditions you experience in addition to cancer, often called co-existing conditions, should be discussed with your cancer care team so they can work with you and your other health care providers to minimize the following risks:

Interactions between cancer drugs and medications for another chronic condition

Aggravation of a chronic condition by the cancer or cancer treatment

Interruptions to cancer treatment due to health problems caused by another chronic condition

A slower recovery after cancer treatment because of another chronic condition

Considerations for specific chronic conditions

When establishing a cancer care plan, it is important to understand how a chronic condition may affect the cancer treatment and your body’s reaction to it. Discuss the following conditions, or any other medical problems you may have, with your doctor or another member of your health care team.

Diabetes. If you have diabetes, closely monitor and control your blood glucose (blood sugar) levels during cancer treatment. Radiation therapy and some types of chemotherapy may cause blood glucose levels to rise. In addition, lack of physical activity, stress, and some treatment side effects, such as vomiting and the inability to eat because of nausea, often affect blood glucose levels. Diabetes may also make it harder for the body to fight infection, which is a risk of many cancer treatments.

Frequently measuring your blood sugar level and taking low-sugar food supplements and anti-nausea medications can help you manage diabetes so it does not interrupt your cancer treatment. Your doctor may ask you to record your blood glucose levels in a diary so that your blood glucose control can be reviewed at your clinic visits. Your doctor may also recommend using fast-acting insulin as a supplement to your normal insulin during cancer treatment.

Heart disease. If you have a heart condition, it is important to know that some types of chemotherapy can make heart problems worse or increase the risk of congestive heart failure, which is a condition in which the heart cannot pump enough blood to the rest of the body. These include drugs from the anthracycline family, such as daunorubicin (Cerubidine, Rubidomycin), doxorubicin (Adriamycin), epirubicin (Ellence), and idarubicin (Idamycin), in addition to trastuzumab (Herceptin), a targeted therapy. Other cancer drugs, such as sorafenib (Nexavar), can cause blood pressure to rise, which may require a change in blood pressure medication. Some medications taken for heart conditions may also interact with certain types of chemotherapy. Finally, receiving radiation therapy near the heart or a combination of chemotherapy and radiation therapy has the potential to cause heart problems.

A doctor who specializes in treating heart diseases, called a cardiologist, may prescribe medications, such as angiotensin-converting enzyme (ACE) inhibitors or beta-blockers, to help protect your heart during cancer treatment. The doctor will test your heart function and blood pressure regularly to ensure your heart condition is being managed properly if you are at risk of developing complications.

Mental health issues. If you have depression or anxiety, talk with your doctor about how to manage these conditions during your cancer treatment. Depression and anxiety often interfere with your ability to participate in the treatment decision-making process and make it more difficult for you to follow through with day-to-day responsibilities, including taking medication and having important screenings or tests. These conditions may also keep you from seeking family and social support during treatment. Antidepressants or anti-anxiety medications, individual or group counseling, and cancer support groups can help you manage your mental health.

Some patients may be asked by their doctor to change or temporarily stop taking medications to manage depression or anxiety as they may interact with your cancer treatment or supportive medications. For example, women whose treatment plan for breast cancer includes the hormone therapy tamoxifen (Nolvadex, Soltamox) should talk with their doctor about any antidepressant medication they may be taking because of potential interactions between tamoxifen and certain antidepressants.

Lung disease. If you have emphysema (a lung disease in which patients have difficulty breathing), chronic obstructive pulmonary disease (a lung disease that causes loss of lung function), or another type of lung disease, talk with your doctor about which chemotherapy will have the least affect on your lung function.

Kidney disease. If you have kidney failure or decreased kidney function, it can be difficult for your body to process some types of chemotherapy, increasing your risk for further kidney problems or other health issues. Dialysis, a procedure that cleans the blood when the kidneys cannot, may filter chemotherapy out of your system before it has a chance to work, so it is important to coordinate dialysis treatments with your oncologist before starting chemotherapy.

Dental and oral health problems. If you have ongoing dental or oral health problems, tell your dentist and dental hygienist about your cancer treatment and make sure your oncologist is aware of the specific issues as well. Some types of chemotherapy may put you at higher risk for infection or bleeding and can cause sores in the mouth or throat. Radiation treatment to the head and neck can also cause mouth sores and increase tooth decay. In addition, some drugs used to treat patients with cancer can cause dental health problems. For instance, drugs called bisphosphonates, which are sometimes used to strengthen bones when cancer has spread to the bones, can increase the risk of a rare type of jaw disease. If possible, try to have dental work done before your treatment begins or schedule it after completing treatment. Depending on the nature of your dental problems, your doctor may want you to see an oncologic dentist (a dentist who specializes in treating people with cancer). Learn more about dental and oral health.

Talking with your doctor

When you meet with your doctor to discuss cancer treatment options, bring your personal medical record (your complete medical history), which should outline any chronic conditions you may have; the medications you are taking, including the dosage, how often you take the medication, and any side effects you have experienced; drug allergies (and any other allergies you may have), including what you experienced when you took a medication you are allergic to; previous surgeries or medical procedures; medical tests and results; and the names of your other doctors, including contact information. This information will help the doctor better coordinate your care and minimize the risk of complications.

Some patients may be asked to temporarily stop taking some of their current medications because of potential interactions with cancer treatments or supportive care. Sometimes the side effects of cancer treatment can make it unsafe to take specific medications. If you are unsure about which medications you should be taking, talk with your doctor or pharmacist.

It is also important to ask questions to learn more about how your chronic conditions may affect your cancer and cancer treatment. Consider asking the following questions:

What are my treatment options?

What is the goal of each treatment?

What treatment plan do you recommend and why?

How will this treatment affect my chronic condition(s)? Will it make the condition(s) worse?

What is the best way for me to manage my chronic condition(s) during treatment?

Will I need additional or different medications, tests, or screenings during treatment to control my chronic condition(s)?

How can I reduce potential side effects or health problems related to my cancer treatment?

How will you work with my other health care providers to share health information and manage my care?

Cancer.Net provides timely, comprehensive, oncologist-approved information from the American Society of Clinical Oncology (ASCO), with support from the Conquer Cancer Foundation. Cancer.Net brings the expertise and resources of ASCO to people living with cancer and those who care for and about them to help patients and families make informed health care decisions.